External validation cohorts demonstrated comparable patterns, with the Duke dataset (N=94) showing a similar age distribution (59/94, 63%, aged 40-60 years), HER2-positivity rate (26/94, 28%), and hormone receptor (HR) profiles, while the SEER cohort (N=2760) maintained consistent invasive ductal carcinoma predominance (2506/2760, 90.8%) and staging trends. The gene discussed is ERBB2; the disease is invasive ductal breast carcinoma.